Quantum dots and other quantum nanoparticles have been prepared and their properties have been well documented and described. One important proposed use of quantum dots, nanoparticles, and magic clusters is in the field of biochemistry wherein these particles provide photoluminescent markers for whole cells, as well as markers that allow one to track the activity of individual cellular ligands, for example, organelles or macromolecules.
One drawback of CdSe magic clusters is their low photoluminescence efficiency. The photoluminescence efficiency for CdSe magic clusters is less than 5%, and typically less than 1%. These low quantum efficiencies provide a barrier to successful tracking of individual nanoparticle/ligand complexes. In addition, the prior art nanoparticles have sizes that do not allow the particles to be easily absorbed through the cellular membrane, even in the instances wherein the particles are complexed with a substrate that easily cross the cell wall. Further limiting is the fact these particles can only be prepared in small amounts under controlled laboratory conditions, inter alia, under an inert atmosphere, at high temperatures, and using special isolation techniques.
There is now a need in the art for Pb-chalcogen (PbS, PbSe, and PbTe) magic clusters that have high photoluminescence efficiencies and that can be prepared on a large scale without the need for specialized equipment and conditions.
Advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.